In an interview with Frontier Psychiatrist, McGilchrist cites two main influences on his work: the psychiatrist John Cutting, and the Chicago psychologist David McNeill. McGilchrist states: "What I began to see – and it was John Cutting's work on the right hemisphere that set me thinking – was that the difference lay not in what they [the two hemispheres] do, but how they do it."^[5] In the same interview, the author explains: "Some very subtle research by David McNeill, amongst others, confirms that thought originates in the right hemisphere, is processed for expression in speech by the left hemisphere, and the meaning integrated again by the right (which alone understands the overall meaning of a complex utterance, taking everything into account)."^[5]

The 608-page book is about the specialist hemispheric functioning of the brain. The differing world views of the right and left brain (the "Master" and "Emissary" in the title, respectively) have, according to the author, shaped Western culture since the time of the ancient Greek philosopher Plato, and the growing conflict between these views has implications for the way the modern world is changing.^[1]

The book is divided into an introduction, two parts and a conclusion. In the introduction, McGilchrist states that "there is, literally, a world of difference between the [brain] hemispheres. Understanding quite what that is has involved a journey through many apparently unrelated areas: not just neurology and psychology, but philosophy, literature and the arts, and even, to some extent, archaeology and anthropology."^[6]

Part One: The Divided Brain edit

In "The Divided Brain", McGilchrist digests study after study, replacing the popular and superficial notion of the hemispheres as respectively logical and creative in nature with the idea that they pay attention in fundamentally different ways, the left being detail-oriented, the right being whole-oriented. These two modes of perception cascade into wildly different hemispheric personalities, and in fact reflect yet a further asymmetry in their status, that of the right's more immediate relationship with physical bodies (our own as well as others) and external reality as represented by the senses, a relationship that makes it the mediator, the first and last stop, of all experience.

Part Two: How the Brain Has Shaped Our World edit

In the second part, "How the Brain Has Shaped Our World", the author describes the evolution of Western culture, as influenced by hemispheric brain functioning, from the ancient world, through the Renaissance and Reformation; the Enlightenment; Romanticism and Industrial Revolution; to the modern and postmodern worlds which, to our detriment, are becoming increasingly dominated by the left brain.

The book received mixed reviews in various newspapers and journals. Reviewing The Master and His Emissary in the American Journal of Psychiatry, Jacob Freedman wrote the book “valiantly addresses the effect hemispheric asymmetry has had on Western civilization" and that it chronicled "how the left brain's determined reductionism and the right brain's insightful and holistic approach have shaped music, language, politics, and art."^[7] A review by Bryan Appleyard in Times Online described the book as suggesting "we are thinking more and more like machines, and risk losing what makes us human",^[8] while David Cox in the Evening Standard wrote that the author "shows convincingly that the degeneracy of the West springs from our failure to manage the binary division of our brains."

In a positive review in The Guardian, philosopher Mary Midgley wrote that the book "points out the complexity, the divided nature of thought itself and asks about its connection with the structure of the brain,"^[9] and that "though neurologists may well not welcome it because it asks them new questions, the rest of us will surely find it splendidly thought-provoking."^[9] In another positive review in Standpoint magazine, Professor Adam Zeman wrote that McGilchrist "extends [the] received wisdom with a hugely ambitious, absorbing and questionable thesis: the two hemispheres have radically contrasting personalities; that they live in a state of creative tension, sometimes declining into open war; and that their struggle for supremacy provides the key to understanding the major cultural movements of human history.^[10] In the Times Literary Supplement, W. F. Bynum wrote: "McGilchrist's careful analysis of how brains work is a veritable tour de force, gradually and skilfully revealed. I know of no better exposition of the current state of functional brain neuroscience."^[11]

In a mixed review in Literary Review, A. C. Grayling wrote that the book was "beautifully written, erudite, fascinating and adventurous," but added that "the findings of brain science are nowhere near fine-grained enough yet to support the large psychological and cultural conclusions Iain McGilchrist draws."^[2] A negative review in The Economist stated that the book resorted to "generalisations of breathtaking sweep" and that the second part of the book "has plainly become untethered from its moorings in brain science."^[12] Likewise, Michael Corballis said of the work, that "Although widely acclaimed, this book goes far beyond the neurological facts."^[13]

Owen Flanagan alleged many shortcomings of the book and delivered a dismissive statement: "The fact is, hemispheric differences are not well understood. Neither are patterns over 2,500 years of western history. Trying to explain the ill-understood latter with a caricature of the former does little to illuminate either."^[14] McGilchrist wrote scathingly of this review, saying: "But anyone who has read my book and reads that review will realise what a shameful piece of writing it is," picking on what he alleges to be evidence of superficiality and misrepresentation.^[15]

The book has inspired a documentary, The Divided Brain, authorised by McGilchrist.^[16]

• McGilchrist, Iain (2009). The Master and His Emissary. Yale University Press. ISBN 978-0-300-14878-7.

• Lateralization of brain function
• Modernism
• Philosophy of mind
• Sociocultural evolution
• Bicameral mentality: A related theory by Julian Jaynes based in communication between the brain hemispheres
• The Matter with Things: A follow-on book by Iain McGilchrist (2021)

• Jaynes, Julian (2000). The Origin of Consciousness in the Breakdown of the Bicameral Mind. Boston, Massachusetts, USA: Houghton Mifflin. ISBN 0-618-05707-2. (Paperback) First published 1976.
• Ornstein, Robert (1998). The Right Mind: Making Sense of the Hemispheres. Harcourt Brace International. ISBN 978-0-15-600627-9.
• Dreher, Rod (16 January 2023). "Maybe Our Culture Is Literally Crazy". The American Conservative. Archived from the original on 20 January 2023. Retrieved 20 January 2023.

Essays edit

• McGilchrist, Iain (2 January 2010). "The Battle of the Brain: The mind's great conflict spills over onto the world stage". The Wall Street Journal. Retrieved 2010-01-03.

Interviews edit

• Vedantam, Shankar (4 Feb 2019). "One Head, Two Brains: How The Brain's Hemispheres Shape The World We See" (Audio podcast). NPR Hidden Brain. Retrieved 2019-02-08. A transcript is also available.
• Mitchell, Natasha (19 June 2010). "The Master and his Emissary: the divided brain and the reshaping of Western civilisation" (Audio podcast). ABC Radio National All in the Mind. Retrieved 2010-06-23. A transcript is also available.
• Staff (4 February 2010). "Interview with Iain McGilchrist". Frontier Psychiatrist. Retrieved 2010-02-05.
• Crispin, Jessa (3 February 2010). "An Interview with Iain McGilchrist". Bookslut. Retrieved 2010-02-03.
• Staff (14 November 2009). "Two worlds of the left and right brain" (Audio podcast). BBC Radio 4 Today. Retrieved 2009-12-24.

Lectures edit

• McGilchrist, Iain (17 Nov 2010). "The Divided Brain and the Making of the Western World" (Video). The Royal Society for the encouragement of Arts, Manufactures & Commerce (RSA). Retrieved 2011-01-26.

Parts of this lecture were republished by the RSA in October 2011 as one of a series of "RSA Animates" with cartoonist Andrew Park's illustrations.^{[L 1]} The twelve-minute animation accompanying McGilchrist's talk took Park two months to complete.^{[L 2]}

• McGilchrist, Iain (May 2011). "Things Are Not What They Seem" (Video). Schumacher College. Retrieved 2011-06-05.
• McGilchrist, Iain (4 May 2012). "Big Ideas: Dr. Iain McGilchrist on The Divided Brain: Our Mind at War" (Video). TVOntario. Retrieved 2015-12-21.
• McGilchrist, Iain (26 October 2012). "Iain McGilchrist on the divided brain's impact on our world" (Video). TVOntario. Retrieved 2015-12-21.

Documentaries edit

• The Divided Brain documentary (2019)

Other reviews edit

• Crispin, Jessa (21 December 2009). "Half and Half". The Smart Set. The Pennoni Honors College, Drexel University. Retrieved 2010-01-04.
• Flanagan, Owen (21 December 2009). "The vast left-brain conspiracy". New Scientist CultureLab blog. Retrieved 2009-12-21.
• Iana, Cristina (27 November 2009). "Studiu: Emisferele cerebrale dreaptă şi stângă au personalităţi opuse" [Study: right and left cerebral hemispheres have opposite personalities] (in Romanian). adevarul.ro international. Retrieved 2009-12-24.
• Vernon, Mark (22 January 2010). "What the other half doesn't know". Philosophy and Life Blog. Retrieved 2010-01-28. Vernon, a writer, journalist and columnist with The Guardian, writes: "At last! A book on neuroscience that is a thrilling read, philosophically astute and with wonderful science."
• Williams, Ray. B. (22 February 2010). "Why we need to use both sides of our brain". National Post (blog). Retrieved 2010-02-22.
• Kingerlee, Roger; Testa, Rita (2011). "Review of The Master and his Emissary". Neuropsychoanalysis. 12 (2). Karnac Books for the International Neuropsychoanalysis Society: 222–226.
• Ellis, Robert M. (10 January 2012). "'The Master and his Emissary' by Iain McGilchrist: An Extended Review". Middle Way Society. Retrieved 2015-08-12.
• Gare, Arran (2012). "Review of 'The Master and his Emissary' by Iain McGilchrist". Cosmos and History: The Journal of Natural and Social Philosophy, Vol 8, No 1 (2012). 8 (1): 412–449.

• Brain Matters: The divided mind. Has our civilisation suffered from a failure to manage the binary division of our brains? Talk given by McGilchrist at the Wellcome Collection in April 2012
• Author's profile at All Souls College, University of Oxford
• The Divided Brain and the Making of the Western World. RSA Keynote by Iain McGilchrist